1. Field of the Invention
The present invention relates to fluorine-containing betaine compounds, and production and use thereof. Particularly, it relates to novel fluorine-containing betaine compounds, a process for their preparation and their use as additives for foam fire-extinguishing agents for polar organic liquids.
2. Description of the Prior Art
Conventional foam fire-extinguishing agents for polar organic liquids such as alcohols and ketones are classified into the following two groups: (1) compositions comprising a partially hydrolyzed protein and (2) compositions comprising a synthetic surface active agent. As the composition of the group (1), there is known a composition comprising a partially hydrolyzed protein and, as an additive for improvement of liquid resistance and thermal resistance, a metal salt of a fatty acid dissolved in an aminoalcohol. As the composition of the group (2), there are known a composition (2-1) comprising a foaming surface active agent and, as an additive for the same purpose as in the group (1), a metal salt of a fatty acid dissolved in an aminoalcohol and a composition (2-2) comprising a foaming surface active agent and, as an additive, a water-soluble high polymer such as sodium alginate.
Although these compositions possess a fire-extinguishing ability, each of them has certain drawbacks as mentioned below. In the composition belonging to the group (1), a water-insoluble metal salt of a fatty acid is dispersed in an aqueous solution of a partially hydrolyzed protein so that precipitation is apt to occur during storage for a long time. When the composition is admixed with water at the site of a fire, it must be used within several minutes, because otherwise a precipitate is formed in the water stream which causes a marked decrease of the fire-exinguishing effect. Further, pouring of foams onto the combustive liquid surface should be effected very quietly, or else rapid disappearance of foams is caused to reduce the effect. In some polar organic liquids such as alcohols, ketones, esters and ethers, an insoluble film is formed on the liquid surface and a relatively high effect can be obtained. But in case of amines, aldehydes, carboxylic acids and other similar polar organic liquids, foams are rapidly dissolved in the organic liquid and disappear because of the presence of a metal salt of a fatty acid so that a desirable effect can not be expected.
In compositions belonging to the group (2-1), precipitation during storage or after admixture is hardly caused, but the fire-resistance is insufficient because a synthetic surface active agent is used as the main ingredient, and besides the liquid resistance is inferior in comparison with the group (1). In compositions belonging to the group (2-2), it is expected to cause formation of an air-containing, floating layer in a gel form having a good liquid resistance on the surface of the polar organic liquid by the interaction between the organic liquid and a natural or synthetic high polymer. But, the effect is inferior in comparison with the groups (1) and (2-1). Since the reagent has a high viscosity, a problem is caused in suction and admixture in practical use.
Further, in all of the above mentioned foam fire-extinguishing agents, sea water or standing water is often used at fire-extinguishing, so that precipitation is caused immediately after admixture because of the presence of metal salts contained in sea water or standing water, which results in marked decrease of the fire-extinguishing effect.
On the other hand, aqueous foam compositions comprising water and fluoroalkyl group-containing compounds have been widely employed for fire-exinguishing in oily fire. For example, a foam fire-extinguishing agent comprising derivatives of fluorocarboxylic acid or fluorosulfonic acid is disclosed in Japanese Patent Publication No. 20080/1965. This composition is a foam fire-extinguishing agent usually called "light water" and employed for fire-extinguishing in oily fire. It forms an aqueous film on the oil surface to prevent evaporation of inflammable vapor from the oil surface. Although this fire-extinguishing agent is thus effective for fire-extinguishing in oily fire, an advantageous fire-extinguishing effect cannot be expected in case of fire of polar organic liquids, because an aqueous film is not formed on the liquid surface.
As other type of fire-extinguishing agents for oily fire, there are known protein foam fire-extinguishing agents, of which a typical example is a composition comprising a protein fire-extinguishing compound and a fluorine-containing surface active agent as an additive. For instance, Japanese Patent Publication No. 21078/1972 discloses that, the incorporation of a small amount of a perfluoroalkyl group-containing, water-soluble surface active agent into a hydrolyzed protein is effective in enhancement of the fluidity and fire resistance of fire-extinguishing foams. In fact, all the water-soluble non-ionic or anionic surface active agents having a perfluoroalkyl group as specifically exemplified therein produce an excellent enhancement in oil fire. However, none of them can produce foams of sufficient stability in fire due to polar organic liquids and are practically usable for such fire. Besides, the said patent publication teaches that cationic surface active agents show a tendency to cause precipitation in the fire-extinguishing composition and therefore their use is not desirable.